1. Field Of The Invention
This invention relates to an apparatus for controlling the flow of a fluid from one zone or area to another, and in particular, to a submerged weir apparatus for effecting such control.
While the apparatus of the present invention is primarily intended for use in wastewater systems, it will be appreciated that the apparatus can also find use in other systems involving the flow of fluids such as between chemical reaction, water treatment, or other zones. The usual method for controlling the flow of water in wastewater treatment systems involves the use of mechanical valves and gates which are relatively expensive to manufacture and maintain, and which may cause significant head loss and unstable hydraulic patterns in the systems. Moreover, it is often difficult to use valves and gates for controlling flow rates between zones or areas of baffled reactors. Finally, it is not economically feasible to use existing systems for accurately and evenly distributing water between zones with flow over long weir lengths, while simultaneously controlling the flow between one treatment zone or area and another zone or area.
2. Discussion Of The Prior Art
The present invention is based on the knowledge that fluid pressure can be used to control liquid distribution in wastewater treatment systems. Searches in the North American patent literature disclosed U.S. Pat. Nos. 796,672, issued to A. Priestman on Aug. 8, 1905; U.S. Pat. No. 899,750, issued to S.F. Miller on Nov. 17, 1908; U.S. Pat. No. 1,063,595, issued to L.E. Rein on Jun. 3, 1913; U.S. Pat. No. 2,823,692, issued to E. Riis-Carstensen on Feb. 18, 1958; U.S. Pat. No. 4,015,629, issued to T.H. Morgan et al on Apr. 5, 1977; U.S. Pat. No. 4,024,060, issued to C.D. Hughes on May 17, 1977; U.S. Pat. No. 4,596,658, issued to M.G. Madt on Jun. 24, 1986; and U.S. Pat. No. 4,883,602, issued to M.H. Anderson on Nov. 28, 1989. These patents teach the use of vacuum and/or gas pressure for controlling the flow of water between chambers or zones or out of treatment systems. In general, the patented apparatuses are not economically feasible, somewhat complicated or rely on inaccurate, passive, and ineffective methods to control flow. In contradistinction, the present invention is low cost, relatively simple to operate, much more effective for flow control, and involves active flow control using a gas under pressure which can be combined with an external flow or depth of water detector and a connected control unit to actively adjust and control the gas pressure and hence accurately control the flow at all times.